Greetings! The delta Taq was actually developed here at Washington University
by Dr. Wanyne Barnes. His common name for it is Klen-Taq and he exclusively uses it for PCR. He'll often use upwards of 50U in a reaction for long PCRs. Like try lengths of 17kb!!! I personally have obtained 5 kb PCR fragments using
the enzyme. Because of patent rights by Cetus, USB doesn't want to deal with
the legal hassles of adveritsing it for PCR, but in fact, that's what Wayne
designed it for. What do I mean by designed? Wayne whacked off the 5' end
of the polymerase so that Klen-Taq (Delta-Taq) has virtually no exonuclease
activity. It and Hot Tub are the best PCR enzymes we've ever used in our lab.
According to Wayne and his tests, Vent polymerase actually has an unacceptably
high exonuclease activity such that one can even lose restriction sites that
were designed in your oligos. I hope this is of use to you "netters"!
David L. Haviland
haviland at kids.wustl.edu